Prime Minister Stephen Harper and U.S. President Barack Obama recently spoke by phone to discuss the ongoing humanitarian crisis in Iraq, where a number of religious minorities have been targeted by Sunni militants.

According to a statement released Tuesday afternoon, Harper and Obama agreed to co-operate in bringing “immediate humanitarian assistance” to Iraqi civilians threatened by members of the Islamic State. The militant group has seized many cities and towns in Iraq and Syria, and has reportedly killed, converted or driven out all non-Sunni Muslims living in those areas.

U.S. and British forces recently airdropped water, food and supplies to thousands of Yazidis, who remain trapped on a mountain and surrounded by Islamic State forces in Iraq. The Yazidis are among those religious groups targeted by the Sunni militants.

Some escaped the Islamic State siege earlier this week thanks to a U.S. airstrike, but many remain trapped.

Harper and Obama also discussed the need for greater unity in the Iraqi parliament, which has struggled to include the many religious factions and ethnicities living in the country.

Iraqi PM Nouri al-Maliki recently accused the country’s newly-elected president, Fouad Massoum, of violating Iraq’s constitution.